Tuning superconductivity in twisted bilayer graphene

@article{Yankowitz2019TuningSI,
  title={Tuning superconductivity in twisted bilayer graphene},
  author={Matthew Yankowitz and Shaowen Chen and Hryhoriy Polshyn and Yuxuan Zhang and K. Watanabe and Takashi Taniguchi and David E. Graf and Andrea F. Young and Cory R. Dean},
  journal={Science},
  year={2019},
  volume={363},
  pages={1059 - 1064}
}
Upping the pressure in bilayer graphene The discovery of superconductivity and exotic insulating phases in twisted bilayer graphene has established this material as a model system of strongly correlated electrons. To achieve superconductivity, the two layers of graphene need to be at a very precise angle with respect to each other. Yankowitz et al. now show that another experimental knob, hydrostatic pressure, can be used to tune the phase diagram of twisted bilayer graphene (see the… 
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References

SHOWING 1-10 OF 101 REFERENCES
Unconventional superconductivity in magic-angle graphene superlattices
TLDR
The realization of intrinsic unconventional superconductivity is reported—which cannot be explained by weak electron–phonon interactions—in a two-dimensional superlattice created by stacking two sheets of graphene that are twisted relative to each other by a small angle.
Electrostatic effects, band distortions, and superconductivity in twisted graphene bilayers
  • F. Guinea, N. Walet
  • Physics, Medicine
    Proceedings of the National Academy of Sciences
  • 2018
TLDR
It is shown that the modulation of the charge density significantly modifies the electronic structure, which can make an important contribution to superconductivity through electron-assisted hopping.
Kohn-Luttinger Superconductivity in Twisted Bilayer Graphene.
We show that the recently observed superconductivity in twisted bilayer graphene (TBG) can be explained as a consequence of the Kohn-Luttinger (KL) instability which leads to an effective attraction
Twisted Bilayer Graphene: A Phonon-Driven Superconductor.
TLDR
It is shown that phonon-mediated electron attraction at the magic angle is strong enough to induce a conventional intervalley pairing between graphene valleys K and K^{'} with a superconducting critical temperature T_{c}∼1  K, in agreement with the experiment.
Mean-field theory for superconductivity in twisted bilayer graphene
Recent experiments show how a bilayer graphene twisted around a certain magic angle becomes superconducting as it is doped into a region with approximate flat bands. We investigate the mean-field
Origin of Mott Insulating Behavior and Superconductivity in Twisted Bilayer Graphene
A remarkable recent experiment has observed Mott insulator and proximate superconductor phases in twisted bilayer graphene when electrons partly fill a nearly flat mini-band that arises a `magic'
Singlet superconductivity enhanced by charge order in nested twisted bilayer graphene Fermi surfaces
Abstract Using the continuum model for low energy non-interacting electronic structure of moire van der Waals heterostructures developed by Bistritzer and MacDonald [1], we study the competition
Origin of Magic Angles in Twisted Bilayer Graphene.
TLDR
A fundamental continuum model for TBG is reported which features not just the vanishing of the Fermi velocity, but also the perfect flattening of the entire lowest band.
Superconductivity from valley fluctuations and approximate SO(4) symmetry in a weak coupling theory of twisted bilayer graphene
AbstarctThe recent discovery of the Mott insulating and superconducting phases in twisted bilayer graphene has generated tremendous research interest. Here, we develop a weak coupling approach to the
Charge-transfer insulation in twisted bilayer graphene
We studied the real space structure of states in twisted bilayer graphene at the `magic angle' $\theta = 1.08^\circ$. The flat bands close to charge neutrality are composed of a mix of `ring' and
...
1
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4
5
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